class Animal:
    def __int__(self, species, sound):
        if species in ['猫', '狗', '猴子', '老虎','大象']:
            self.species = species
            self.sound = sound
        else:
            self.species = None
            self.sound = None
        def speak(self):
            if self.species ==None:
                print('动物园里没有动物，游戏结束！ ')
                return  False
            else:
                print(self.species, sound)
                return True
            print('动物园有什么？ ')
